1. Field of the Invention
The present invention relates to apparatus and methods for particle beam systems.
2. Description of the Background Art
Organic and other contaminants can adversely affect the measurement accuracy, inspection and review data, and other information received from a scanning electron microscope (SEM) or similar apparatus. This is true even when the organic contaminants are present only at low levels. In addition, contaminants can adversely reduce the lifetime of key electron beam (e-beam) tool components and increase the frequency at which such tools need servicing.
A conventional method 100 for semiconductor manufacturing, including a level of contaminant removal, is shown in the flow chart of FIG. 1. A semiconductor wafer is provided (102) in a “clean room” environment, and the wafer is cleaned (104) at a contaminant removal station to remove contaminants thereon. Thereafter, the wafer goes through various process steps. These process steps may include, for example, various deposition, lithography, etching, and other steps. After one or more of these process steps (106) (i.e. at some point during the process), it may be desired to inspect the wafer to check for defects or to gather other information. The wafer is then transported (108) to an e-beam inspection station. This transportation (108) is generally performed within the clean room environment to avoid undue contamination. The e-beam inspection station may comprise, for example, a tool based on an SEM. At the e-beam inspection station, the wafer may be scanned or otherwise inspected (110). Thereafter, the manufacturing process may continue with further process steps (112) and so on. Each time e-beam inspection is performed, the wafer is typically exposed but in the clean room environment.